Question

calculate the number of miles and molecules and atoms present in 0.8g of helium gas

Answer 1

• 1 mole of Helium contains 4 g of Helium (Molecular weight of Helium)
So, X moles of Helium will contain 0.8 g of Helium.
So, X = 0.8 ÷ 4
So, X = 0.2 mole of Helium

• 4 g of Helium which is 1 mole contains 6.022 × 10^23 atoms of Helium.
Thus, 0.8 g of Helium will contain Y atoms of Helium
So, Y = (0.8 × 6.022 × 10^23) ÷ 4
So, Y = 0.2 × 6.022 × 10^23
So, Y = 1.2044 × 10^23 atoms of Helium